Malvaceae

Malvaceae, commonly known as mallows, comprises a diverse family of flowering plants encompassing approximately 244 genera and boasting a rich tapestry of 4,225 known species. This botanical family holds considerable economic significance, featuring several well-known members such as okra, cotton, cacao, roselle, and durian.

1.0Classification of Malvaceae

2.0General Characters of Malvaceae

1. Vegetative Characters

Habitat: Members of the Malvaceae family exhibit diverse growth forms; they can be herbs, shrubs and rarely small and large trees. 

Root: Tap root system with branches. 

Stem: Malvaceae includes herbaceous or woody plants with an erect, branched growth pattern, often adorned with stellate hairs. The stems are characterized by mucus canals and cavities. 

Leaves: The leaves of the Malvaceae family are typically alternate, stipulated, having stellate hairs. It can vary from simple to palmately lobed or compound with palmate venation. While the majority have entire margins, some species exhibit dentate margins. 

2. Floral characters

Inflorescence: The inflorescence may be cymose or solitary flower that may be terminal and axillary.

Flower : Flowers in the Malvaceae family are typically bisexual, containing both male (stamens) and female (pistil) reproductive organs. Flowers exhibit actinomorphic symmetry, meaning they are radially symmetrical with hypogynous ovary.  

Epicalyx :  Epicalyx (Bracteoles) Characteristics in Malvaceae, numbering 3 to 7, manifests as free and green structures in Malvaceae flowers. These represent transformed bracteoles, sharing a structural similarity with bracts present on the pedicel. The bracteoles exhibit valvate aestivation.

Calyx: Sepals in Malvaceae number 5, forming a gamosepalous structure with valvate aestivation. Some plants exhibit a persistent calyx, meaning that the sepals remain attached to the mature fruit. Notable examples include Abelmoschus (Bhindi/Okra) and Gossypium (Cotton).

Corolla: The petals in Malvaceae are typically 5 in number, forming a polypetalous arrangement with twisted aestivation. These petals are often mucilaginous.

Androecium: In Malvaceae, stamens are numerous and joined in one bundle (monadelphous), while the anthers stay separate. The anthers have a kidney-shaped appearance and are monothecous. The filaments unite to create a long staminal tube around the style. Importantly, this staminal tube is attached to the base of the petals, making the stamens epipetalous. 

Gynoecium: The gynoecium in Malvaceae is either pentacarpellary or polycarpellary, displaying syncarpous features. However, the stigmas are free, resulting in an incompletely syncarpous structure. The ovary is pentalocular or multilocular, with the number of locules corresponding to the carpels. The ovary and style are ensconced within the staminal tube, while the stigma remains outside. Axile placentation is observed in the arrangement of ovules within the ovary.

Pollination: Self-pollination is often avoided by means of protandry. Most species are entomophilous (pollinated by insects). 

Fruits and Seed: The fruit in Malvaceae exhibits diverse forms, including loculicidal capsules or schizocarps and occasionally berries and seeds are typically numerous, and their embryos are curved. Notably, the endosperm is absent in Malvaceae seeds.

3.0Floral Formula of Malvaceae

Common floral formula of malvaceae family-

Ebr ⊕ ♀ ♂  Epi5 – 8  K(5) C5  Aα  G(5)

4.0Floral Diagram of Malvaceae

5.0Important Plants of Malvaceae

Some of the important plant species of malvaceae family are listed below:

• Musk mallow (A. moschatus)
• Okra (A. esculentus)
• Balsa (Ochroma pyramidale)
• Baobab (genus Adansonia)
• Bombax cotton (genus Bombax)
• Bottle tree (genus Brachychiton)
• Cacao(Theobroma cacao)
• Kapok (C. pentandra)
• Kilk-floss tree (C. speciosa)
• White jute (C. capsularis)
• Tossa jute (C. olitorius)
• Cotton(genus Gossypium)
• Hibiscus (genus Hibiscus)
• Hollyhock (Alcea rosea)
• Mallow (genus Malva)
• • Musk mallow (M. moschata)
  • Tree mallow (M. aborea)
• Marsh mallow (Althaea officinalis)
• Urena(Urena lobata)

6.0Economic Importance of Malvaceae

The economic use of Malvaceae family plants is as a source of natural fibres, the family providing perhaps the world's 3 most important fibre crops. Plants of this family includes many plants of great economic importance e.g. food, fibers, oils, ornamentals, beverages, timber, in traditional medicine, and in horticulture.

• Food: Okra/bhindi(Lady finger) = Abelmoschus esculentus or Hibiscus esculentus used as a vegetable.

• Vegetable Oils: From Cotton seeds (Gossypium seeds). The seeds of Gossypium are used for obtaining oil which is hydrogenated to prepare vegetable ghee.Volatile oil known as Musk seed oil used in perfumery is obtained from Hibiscus abelmoschus seeds.

• Fibers: Most of the economically important fiber yielding plants belong to the family malvaceae examples : Cotton = Gossypium. Patua = Hibiscus sabdariffa (Rosella hemp)  Patsan [Deccan hemp] = Hibiscus cannabinus

• Jute: jute obtained from the phloem fibres of Corchorus capsularis and Corchorus olitorius. Kenaf, obtained from the phloem fibres of Hibiscus cannabinus. Several other species are exploited for their phloem fibres, including devil's cotton, Abroma angusta, China jute, Abutilon theophrastii, roselle, Hibiscus sabdariffa. Kapok, the seed hairs of a number of trees belonging to Bombacoideae, particularly Bombax ceiba, is not spinnable and therefore can't be used for textiles, but is waterproof. It is used primarily for insulation.
• Beverages: Kola nuts, the fruits of Cola nitida and other species, is used commercially as a flavouring ingredient in drinks (colas or kolas). They contain stimulant alkaloids - caffeine and theobromine. Cacao is used in the production of beverages, in addition to chocolate.
• Medicine : Urena repanda - These roots are useful in hydrophobia.
• Ornamental : China rose [Shoe Flower] = Hibiscus rosasinensis - Red shoes polish is obtained from the petals of this flower.